Maybe you know someone who has fits over faulty apostrophe usage. (Can we say "apostrophical usage"? 'Cause it sounds so much zanier.) I know a few such people. Actually, I am "such people," only I usually have apostrophe fits in my head, so you might not know about them.
We could talk about all the nuances of apostrophes' rules, but I just want to talk about plurals and possessives. It's not like I never err in this realm or anything, but I still just don't think the rule is that hard. Basically, you put an apostrophe in when you're talking about something belonging to someone ("apostrophes' rules," for example, or "Jenn's bad memory"), and you leave it out when you're talking about more than one of something (like "apostrophes" or "rehearsals").
Of course, there are always the exceptions, but if we just concentrate, they're not too hard. Sometimes you have to put an apostrophe in when there's more than one of something because it's already an abbreviation and people wouldn't know if that "s" on the end was part of the abbreviation or not. So, like, "DVD's," or "Jenn with two n's."
But today I was mulling this over on my lunch break and I thought, probably those people who came up with the apostrophe rules could have made it easier on everybody (and ditched a lot of the exceptions) if the rule went the other way around. For one thing, almost everybody nowadays puts apostrophes in all plurals, and none in possessives. "Possessive's," or something. Drives me nuts, but if they would have decided it was supposed to be like that in the first place, then there would be so many fewer errors. ("Many fewer"? Eh?)
Then you could have said, "Jenns two n's," instead of "Jenn's two n's," which is just confusing. Plus, it looks weird, and is nearly impossible to say, "Jennwith2n's's blog."